Electronic smoking article

ABSTRACT

A smoking article such as an electronic cigarette is disclosed, which includes an outer housing extending in a longitudinal direction; a capillary wick for holding liquid material; a micro pump system configured to pump a liquid material contained within a liquid supply reservoir through an outlet of the supply reservoir to the capillary wick; a heating arrangement operable to heat at least a portion of the capillary wick to a temperature sufficient to at least initially volatilize the liquid material held within the capillary wick; a power supply operable to apply voltage to the micro pump gas cell to generate a gas to pump the liquid material from the liquid supply reservoir into the capillary wick; at least one air inlet; and whereby air is mixed with the volatilized material to form an aerosol.

RELATED APPLICATION(S)

The present application claims priority under 35 U.S.C. 119 to U.S.Provisional Patent Application No. 61/804,304, filed on Mar. 22, 2013,the entire content of which is hereby incorporated by reference.

SUMMARY

The teachings herein provide embodiments of novel smoking articles suchas electronic cigarettes/cigars and aerosol generators. These devicescan include a capillary wick designed to deliver liquid material from aliquid reservoir to a heater. The devices can be activated by a consumerdrawing on a mouth end of the smoking article to deliver an aerosol tothe user. The teachings include application of a gas cell based micropump as a fluid delivery device in an aerosol based smoke deliverydevice.

In accordance with an exemplary embodiment, an electronic smokingarticle is disclosed, the electronic smoking article comprising: anouter housing extending in a longitudinal direction; a capillary wickfor holding liquid material; a micro pump system configured to pump aliquid material contained within a liquid supply reservoir through anoutlet of the supply reservoir to the capillary wick; a heatingarrangement operable to heat at least a portion of the capillary wick toa temperature sufficient to at least initially volatilize the liquidmaterial held within the capillary wick; a power supply operable toapply voltage to the micro pump gas cell to generate a gas to pump theliquid material from the liquid supply reservoir into the capillarywick; at least one air inlet; and whereby air is mixed with thevolatilized material to form an aerosol.

In accordance with an exemplary embodiment, an electronic smokingarticle is disclosed, the electronic smoking article comprising: aliquid supply reservoir containing a liquid material; and a micro-pumpsystem comprising: an expandable gas chamber comprising a movable wallof the expandable gas chamber and a wall of the liquid supply reservoir;a micro pump gas cell to generate a gas and to direct the gas to theexpandable gas chamber to expand the expandable gas chamber and acapillary wick, wherein expansion of the expandable gas chamber movesthe wall to dispense the liquid material from the liquid supplyreservoir to the capillary wick.

In accordance with an exemplary embodiment, a method of producing anaerosol from an electronic smoking article is disclosed, the methodcomprising: communicating liquid material to a capillary wick using amicro pump system to pump a liquid material from a liquid reservoir tothe capillary wick; and communicating electrical power from a powersource to a heater operative upon at least a portion of the capillarywick, wherein the capillary wick discharges the liquid communicated tothe capillary wick in an at least partially volatized condition into amixing chamber.

In accordance with an exemplary embodiment, a method of improvingwithdrawal of liquid from a reservoir of an electronic smoking articleis disclosed, the method comprising: retaining a liquid in the reservoirwith a fibrous mass; and compressing said fibrous mass by communicatingan output of a gas-cell micro pump with a flexible wall of saidreservoir.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure is explained below with reference to the exemplaryembodiments shown in the drawings. In the drawings:

FIG. 1 is a cross-sectional view of an electronic smoking article inaccordance with an exemplary embodiment; and

FIG. 2 is a cross-sectional view of a portion of an electronic smokingarticle having a micro pump system and a capillary wick in accordancewith an exemplary embodiment.

DETAILED DESCRIPTION

In accordance with an exemplary embodiment, an electronic smokingarticle such as an electronic cigarette or electronic cigars, includes amicro pump system, which pushes a column of liquid material through to acapillary wick. In accordance with an exemplary embodiment, the micropump system comprises a power source in the form of a battery and amicro pump gas cell that generates gas as it discharges to push aplunger or moveable structure, which drives the liquid material out aliquid reservoir at a constant flow rate to the capillary wick.

FIG. 1 shows an electronic cigarette 100 in accordance with an exemplaryembodiment. As shown in FIG. 1, the electronic cigarette 100 includes ahousing 110 having a mouth end 112 and a body end 114. In the body end114, there is provided an electric power supply in the form of battery120 and electric circuitry in the form of circuitry 122 and a puffdetection system 130. The cigarette 100 includes a micro pump system 200which delivers a liquid material 242 (FIG. 2) from a liquid supplyreservoir (or fluid reservoir) 240 to a capillary wick 210 configured tohold a liquid material. In an embodiment, at least a portion of thecapillary wick 210 is adjacent (or surrounded by) the heater 144. Inaccordance with an exemplary embodiment, one end of the capillary wick210 communicates with the fluid reservoir 240 of the micro pump system200. Another end portion of the capillary wick 210 is heated by theheater 144. The heater 144 is connected to the electric circuitry 122via connections (not shown). The housing 110 also includes an air inlet160, an air outlet 162 at the mouth end 112, and an aerosol formingchamber 170.

In use, the liquid material 242 is driven by the micro pump system 200from the fluid reservoir 240 to the capillary wick 210, as shown inFIG. 1. When a user draws on the electronic cigarette 100 at the airoutlet 162, ambient air is drawn through air inlet 160. In accordancewith an exemplary embodiment, the electronic cigarette 100 can include apuff detection system 130, which senses the puff and activates the micropump system 200 and the heater 144. The battery 120 supplies a pulse ofenergy to the heater 144 to heat the end portion of the capillary wick210 adjacent the heater 144. The liquid material 242 in the capillarywick 210 is vaporized by the heater 144 to create a supersaturatedvapor. At the same time, the liquid material 242 being vaporized isreplaced by additional liquid material 242 moving along the capillarywick 210 under (responsive to) a pumping action from the micro pumpsystem 200.

In accordance with an exemplary embodiment, the supersaturated vaporcreated is mixed with and carried in the air flow from the air inlet160. In the aerosol forming chamber 170, the vapor condenses to form aninhalable aerosol, which is drawn through the outlet 162 of the articleduring a puff. As shown in FIG. 1, the circuitry 122 and the puffdetection system 130 are preferably programmable. In accordance with anexemplary embodiment, the circuitry 122 and puff detection system 130can be used to manage the operation of the electronic cigarette. Inaccordance with an exemplary embodiment, the micro pump system 200 inconjunction with the physical design of the electronic cigarette 100 canassist with control of the particle size in the aerosol.

In use, once the capillary wick 210 is heated, the liquid materialcontained and/or held within a heated portion of the capillary wick 210is volatilized and mixes with air and forms an aerosol in a mixingchamber 170. The electronic cigarette 100 also includes at least one airinlet 160 operable to deliver air to the mixing chamber 170. The airinlets 160 to the mixing chamber 170 can be arranged downstream of thecapillary wick 210 so as to minimize drawing air along the capillarywick and thereby avoid cooling of the capillary wick 210 during heatingcycles. In the exemplary embodiment, the at least one air inlet 160includes one or two air inlets 160. Alternatively, the air inlets 160can be three, four, or five or more. In accordance with an exemplaryembodiment, the size and number of air inlets 160 can also aid inestablishing the resistance to draw of the electronic cigarette 100.

The battery 120 can be a Lithium-ion battery or one of its variants, forexample a Lithium-ion polymer battery. Alternatively, the battery 120may be a Nickel-metal hydride battery, a Nickel cadmium battery, aLithium-manganese battery, a Lithium-cobalt battery or a fuel cell. Inaccordance with an exemplary embodiment, the electronic cigarette 100 isusable by a smoker until the energy in the power supply is depleted.Alternatively, the battery 120 may be rechargeable and include circuitry(not shown) allowing the battery to be chargeable by an externalcharging device. For example, the circuitry, when charged, providespower for a pre-determined number of puffs, after which the circuitrymust be re-connected to an external charging device.

The electronic cigarette 100 also includes control circuitry 122, whichcan be on a printed circuit board. Once a switch 180 is pressed, thepower supply is activated and supplies power to the micro pump system200 and the heater 144. The control circuitry 122 can also include aheater activation light (not shown) operable to glow when the heater 144is activated. The control circuitry 122 can also include a timeroperable to limit the time for which power is supplied to the micro pumpsystem 200 and the heater 144. The time-period of the electric currentsupply to the the micro pump system 200 and the heater 144 may bepre-set depending on the amount of liquid desired to be vaporized. Forexample, the control circuitry 122 can be programmable for this purpose.

In accordance with an exemplary embodiment, when activated, the heater144 heats a portion of the capillary wick 210 for less than about 10seconds, more preferably less than about 7 seconds. Thus, the powercycle (or maximum puff length) can range in period from about 1 secondto about 10 seconds.

FIG. 2 is a cross-sectional view of a portion of an electronic cigarette100 having a micro pump system 200 in accordance with an exemplaryembodiment. As shown in FIG. 2, the micro pump system 200 can include amicro pump gas cell 220, a plunger 230, a liquid supply reservoir 240,and a capillary wick 210. In accordance with an exemplary embodiment,the micro pump system 200 is configured to pump a liquid material 242from a liquid supply reservoir 240 through an outlet 244 to a capillarywick 210. In an embodiment, the capillary wick 210 extends into theliquid supply reservoir through the outlet 244.

In accordance with an exemplary embodiment, a power supply in the formof a battery 120 is operable to apply voltage across to a heater 144operable to heat the capillary wick 210 to a temperature sufficient toat least initially volatilize liquid material 242 contained within thecapillary wick 210. The power supply also is operable to apply voltageto the micro pump gas cell 220 to generate a gas 224. The pressure ofthe generated gas 224 moves the plunger 230 along a linear path withinthe micro pump system 200 to drive or pump the liquid material 242 outof the liquid supply reservoir 240 into the capillary wick 210.

As shown in FIG. 2, the micro pump system 200 is configured to pump aliquid material 242 from a liquid supply reservoir 240 through an outlet244 to the capillary wick 210. In accordance with an exemplaryembodiment, the liquid supply reservoir 240 comprises a liquid material242, which is volatilized when heated and forms an aerosol.

In accordance with an exemplary embodiment, a power supply in the formof a battery 120 is operable to apply voltage across to a heater 144operable to heat the capillary wick 210 to a temperature sufficient toat least initially volatilize the liquid material 242 contained withinthe capillary wick 210. The battery 120 can also be operable to applyvoltage to the micro pump gas cell 220 to generate a gas 224. Thegenerated gas 224 moves the plunger 230 along a forward direction in alinear path within the micro pump system 200 to drive the liquidmaterial 242 out of the liquid supply reservoir 240.

In lieu or in addition to the plunger 230, the reservoir 240 may includea flexible wall or bladder in which case the output of the micro-pumpgas cell 220 would compress the flexible wall or bladder to pump fluidfrom the reservoir.

In accordance with an exemplary embodiment, the micro pump gas cell 220forms a first wall of an expandable gas chamber 222 and the moveableplunger 230 forms a second wall of the expandable gas chamber 222. Theplunger 230 also forms a moveable wall of the fluid reservoir 240. Inuse, the micro pump gas cell generates a gas 224 on demand and directsthe gas 224 into the expandable gas chamber 222 to expand the expandablegas chamber 222, wherein expansion of the expandable gas chamber 222moves the plunger 230 in a forward direction along a linear path toreduce a volume of the fluid reservoir 240, which dispenses or pushesthe liquid material 242 from the fluid reservoir 240 to the capillarywick 210.

Simultaneously, to delivering liquid material 242 to the capillary wick210, the power supply 120 is activated and the capillary wick 210 isheated to form a heated section wherein the liquid material 242 isvolatilized.

In accordance with an exemplary embodiment, the capillary wick 210 canbe made from a variety of filamentary porous or capillary materials andpreferably has a known, pre-defined capillarity. Examples includeceramic- or graphite-based materials in the form of fibers or sinteredpowders. Wicks of different capillarity can be used to accommodatedifferent liquid physical properties such as density, viscosity, surfacetension and vapor pressure. In accordance with an exemplary embodiment,the wick 210 can be designed so that the required amount of liquidmaterial 242 can be delivered to the heater 144.

In an exemplary embodiment, the electronic cigarette 100 is about thesame size as a conventional cigarette. In some embodiments, theelectronic cigarette 100 can be about 80 mm to about 88 mm long andabout 7 mm to about 8 mm in diameter. For example, in an exemplaryembodiment, the electronic cigarette 100 is about 84 mm long and has adiameter of about 7.8 mm.

The outer cylindrical housing 110 of the electronic cigarette 100 may beformed of any suitable material or combination of materials. Examples ofsuitable materials include metals, alloys, plastics or compositematerials containing one or more of those materials, or thermoplasticsthat are suitable for food or pharmaceutical applications, for examplepolypropylene, polyetheretherketone (PEEK), ceramic, and polyethylene.

In an exemplary embodiment, the volatilized material formed as describedherein can at least partially condense to form an aerosol includingparticles. The particles contained in the vapor and/or aerosol can rangein size from about 0.5 micron to about 4 microns, for example, about 1micron to about 4 microns. In an exemplary embodiment, the vapor and/oraerosol has a particle size of about 3.3 microns or less. In addition,the particles can be substantially uniform throughout the vapor and/oraerosol.

In accordance with an exemplary embodiment, the liquid material 242includes a tobacco-containing material including volatile tobacco flavorcompounds which are released from the liquid upon heating. The liquidmaterial 242 may also be a tobacco flavor containing material or anicotine-containing material. Alternatively, or in addition, the liquidmaterial 242 may include a non-tobacco material. For example, the liquidmaterial 242 may include water, solvents, ethanol, plant extracts andnatural or artificial flavors. Preferably, the liquid material furtherincludes an aerosol former. Examples of suitable aerosol formers areglycerine and propylene glycol.

The heater 144 preferably includes an electrical heating element. Theheater 144 preferably includes an electrically resistive material.Suitable electrically resistive materials include but are not limitedto: semiconductors such as doped ceramics, electrically “conductive”ceramics (such as, for example, molybdenum disilicide), carbon,graphite, metals, metal alloys and composite materials made of a ceramicmaterial and a metallic material. Such composite materials may includedoped or undoped ceramics.

Examples of suitable doped ceramics include doped silicon carbides.Examples of suitable metals include titanium, zirconium, tantalum andmetals from the platinum group. Examples of suitable metal alloysinclude stainless steel, Constantan, nickel-, cobalt-, chromium-,aluminum- titanium- zirconium-, hafnium-, niobium-, molybdenum-,tantalum-, tungsten-, tin-, gallium-, manganese- and iron-containingalloys, and super-alloys based on nickel, iron, cobalt, stainless steel,Timetal® and iron-manganese-aluminum based alloys. Timetal® is aregistered trademark of Titanium Metals Corporation, 1999 Broadway Suite4110, Denver, Colo. In composite materials, the electrically resistivematerial may optionally be embedded in, encapsulated or coated with aninsulating material or vice-versa, depending on the kinetics of energytransfer and the external physicochemical properties required.

The heater 144 may take any suitable form. For example, the heater 144may take the form of a heating blade. Alternatively, the heater 144 maytake the form of a casing or substrate having differentelectro-conductive portions, or an electrically resistive metallic tube.Alternatively, the heater 144 may be a disk (end) heater or acombination of a disk heater with heating needles or rods.Alternatively, the heater 144 may take the form of a metallic etchedfoil insulated between two layers of an inert material. In that case,the inert material may include Kapton, all-polyimide or mica foil.Alternatively, the heater 144 may take the form of a sheet of material,which may be rolled around at least a portion of the capillary wick.Alternatively, the heater 144 may take the form of an etched foil foldedaround at least a portion of the capillary wick. The etched foil mayinclude a metal sheet cut by a laser or by electro-chemical process. Thesheet may be made from any suitable material, for example, aniron-aluminum based alloy, an iron-manganese-aluminum base alloy orTimetal®. The sheet may be rectangular in shape, or may have a patternedshape, which may form a coil-like structure when rolled around thecapillary wick. Other alternatives include a heating wire or filament,for example, a nickel-chromium (Ni—Cr), platinum, tungsten or alloywire.

In an exemplary embodiment, the heater 144 includes a coil of wire atleast partially surrounding the capillary wick 210. In an exemplaryembodiment, the heater 144 is a metal wire and/or a metal alloy wire.The heater 144 can be a coil, which can extend fully or partially alongthe length of capillary wick 210. The coil may extend fully or partiallyaround the circumference of the capillary wick 210. In anotherembodiment, the coil is not in contact with the capillary wick 210,which allows the heating coil to heat the capillary wick 210 but reduceswastage by not vaporizing more liquid than necessary. This also reducesthe amount of liquid which condenses on the inside walls, therebyreducing cleaning requirements.

The electronic cigarette 100 can include a puff indicator (not shown)for indicating when the heater 144 is activated. In the embodiment inwhich the electric circuitry includes a puff sensor, the indicator maybe activated when the sensor senses air flow indicative of the usertaking a puff. In the embodiment in which the electric circuitryincludes a manually operable switch, the indicator may be activated bythe switch.

In accordance with an exemplary embodiment, the electronic cigarette 100having a micro pump system 200 as shown in FIGS. 1 and 2 can beconfigured to deliver a fluid material 242 at a constant flow rate ofabout 1 to 5 microliters/second. In accordance with an exemplaryembodiment, the micro pump system 200 is configured to displace a totalof about 0.5 to 2.0 milliliters of a liquid material 242 during a lifeof the system with cycle to cycle consistency. For example, theelectronic cigarette 100 having a micro pump system 200 can have a lifeof about 250 cycles, with a cycle duration of up to about 5 seconds anda time between cycles of about 1 second or greater. In accordance withan exemplary embodiment, an outer diameter of the micro pump system 200can be correlated based on capacity and size, for example, less than 8mm for an exemplary embodiment. In addition, the micro pump system 200is preferably isolated from the liquid material 242 and externalenvironment.

Further details of suitable gas-cell micro-pumps are provided in U.S.Pat. Nos. 8,113,390 and 8,353,426, which are incorporated herein byreference, in their entireties.

It is also envisioned that the liquid supply reservoir 240 may include afibrous mass or gauzes(s) to retain the liquid and that the gas-cellpump be operated to move a moveable wall of the reservoir so as tocompress the gauze. Such arrangement could be operated as necessary toassure a more complete and consistent withdrawal of the liquid from thegauze.

The teachings herein are applicable to all forms of electronic smokingarticles, such as electronic cigarettes, cigars, pipes, hookas andothers, regardless of their size and shape.

When the word “about” is used in this specification in connection with anumerical value, it is intended that the associated numerical valueinclude a tolerance of ±10% around the stated numerical value.

Moreover, when the words “generally” and “substantially” are used inconnection with geometric shapes, it is intended that precision of thegeometric shape is not required but that latitude for the shape iswithin the scope of the disclosure. When used with geometric terms, thewords “generally” and “substantially” are intended to encompass not onlyfeatures which meet the strict definitions but also features whichfairly approximate the strict definitions.

It will now be apparent that a new, improved, and nonobvious electroniccigarette has been described in this specification with sufficientparticularity as to be understood by one of ordinary skill in the art.Moreover, it will be apparent to those skilled in the art that numerousmodifications, variations, substitutions, and equivalents exist forfeatures of the electronic cigarette which do not materially depart fromthe spirit and scope of the invention. Accordingly, it is expresslyintended that all such modifications, variations, substitutions, andequivalents which fall within the spirit and scope of the invention asdefined by the appended claims shall be embraced by the appended claims.

What is claimed is:
 1. An electronic smoking article, the electronicsmoking article comprising: an outer housing extending in a longitudinaldirection; a capillary wick for holding liquid material; a micro pumpsystem configured to pump a liquid material contained within a liquidsupply reservoir through an outlet of the supply reservoir to thecapillary wick; a heating arrangement operable to heat at least aportion of the capillary wick to a temperature sufficient to at leastinitially volatilize the liquid material held within the capillary wick;a power supply operable to apply voltage to the micro pump gas cell togenerate a gas to pump the liquid material from the liquid supplyreservoir into the capillary wick; at least one air inlet; and wherebyair is mixed with the volatilized material to form an aerosol.
 2. Theelectronic smoking article of claim 1, comprising: a mixing chamberdownstream of the capillary wick; a mouth end having at least oneoutlet, wherein the mouth end is in fluid communication with the mixingchamber so as to deliver the aerosol to a smoker.
 3. The electronicsmoking article of claim 1, wherein the micro pump comprises: anexpandable gas chamber comprising a plunger forming a wall of theexpandable gas chamber and moving along a linear path, and wherein theplunger forms a wall of the liquid supply reservoir; and a micro pumpgas cell to generate a gas and to direct the gas to the expandable gaschamber to expand the expandable gas chamber, wherein expansion of theexpandable gas chamber moves the plunger in a forward direction alongthe linear path to reduce a volume of the liquid supply reservoir todispense the liquid material from the liquid supply reservoir into thecapillary wick.
 4. The electronic smoking article of claim 3,comprising: a power source connected to the micro pump gas cell; and aswitch coupled to the power source, the switch configured to activatethe micro pump gas cell, and wherein the micro pump gas cell isconfigured to deliver a constant flow rate of liquid material at about0.5 microliters/second to 2.0 microliters/second.
 5. The electronicsmoking article of claim 1, wherein the power source includes a battery.6. The electronic smoking article of claim 1, further including controlcircuitry operable to control supply of power to a heater of the heatingarrangement.
 7. The electronic smoking article of claim 1, wherein theat least one air inlet is located downstream of the capillary wick. 8.The electronic smoking article of claim 1, further including a switchwherein pressure applied to the switch simultaneously activates a heaterof the heating arrangement and micro pump system so as to pump liquidmaterial from the liquid supply reservoir into the capillary wick.
 9. Anelectronic smoking article, the electronic smoking article comprising: aliquid supply reservoir containing a liquid material; and a micro-pumpsystem comprising: an expandable gas chamber comprising a movable wallof the expandable gas chamber and a wall of the liquid supply reservoir;a micro pump gas cell to generate a gas and to direct the gas to theexpandable gas chamber to expand the expandable gas chamber, whereinexpansion of the expandable gas chamber moves the wall to dispense theliquid material from the liquid supply reservoir; and a capillary wickfor holding liquid material in fluid communication with the liquidsupply reservoir.
 10. The electronic smoking article of claim 9, furthercomprising: a power source connected to the micro pump gas cell.
 11. Theelectronic smoking article of claim 10, comprising: a switch coupled tothe power source, the switch configured to activate the micro pump gascell, wherein the micro pump gas cell is configured to deliver aconstant flow rate of liquid material at about 0.5 microliters/second to2.0 microliters/second.
 12. A method of producing an aerosol from anelectronic smoking article, the method comprising: communicating liquidmaterial to a capillary wick using a micro pump system to pump a liquidmaterial from a liquid supply reservoir to the capillary wick; andcommunicating electrical power from a power source to a heater operativeupon at least a portion of the capillary wick, wherein the capillarywick discharges the liquid communicated to the capillary wick in an atleast partially volatized condition into a mixing chamber.
 13. Themethod of claim 12, comprising: generating a gas with a micro pump gascell; and communicating the generated gas with the liquid supplyreservoir to dispense the liquid material from the liquid supplyreservoir to the capillary wick.
 14. A method of improving withdrawal ofliquid from a reservoir of an electronic smoking article, the methodcomprising: retaining a liquid in the reservoir with a fibrous mass; andcompressing said fibrous mass by communicating an output of a gas-cellmicro pump with a flexible wall of said reservoir.